Comment by belorn
9 hours ago
Lets put down some Swedish numbers.
During the coldest winter month, solar energy produce (as per statistics from the solar industry in Sweden) somewhere around 3-7% of the amount produced during the warmest month. Households also consume around 2-4 times the amount of energy during the coldest month compared to the warmest month. Sweden is a country where only a small minority have air conditioning installed at home.
Those are the worst month vs the best month. Overall the winter is not that bad, but it is still pretty bad for solar. Talking with people who has had solar installed here, the general story is very similar. During periods where it do produce the market price is already exceptional low, so it isn't returning a major saving. When the market price is high, the output is low, forcing them to be connected to the grid and pay whatever the electrical company demand during the highest market peaks, as well as taxes and grid fees which themselves has increased to match the cost of high variability.
All this looks very different in countries with much warmer climates and where the major energy consumption from households are air conditioning.
The nice thing is Sweden has lots of hydro, which works as natural long-term energy storage. Every bit of solar you generate means water is kept in the dam for use later in the year.
You also can't ignore wind power which should be part of any plan to "overbuild".
All of the discussions here conveniently ignore the existance of Wind. Which fortunately has higher yield in the months when there is less sun.
Yes, it's a mix. It's always a mix. Arguing that "renewables" = "solar" is a classic straw man.
So is comparing rooftop solar for a single property to grid solar for a country to a continent-sized grid of mixed renewable sources.
Battery and storage tech are barely getting started. Pumped storage is perfectly capable of smoothing out seasonal loads.
There's some capex for physical pumped storage - less than for a nuke plant - but once running it's comparatively low cost.
Yeah but:
1. Sweden is just about the worst case, there's very few countries/people that far north.
2. There's this genius invention called "wires". HVDC has transmission losses on the order of 3.5% per 1,000km. You don't have to colocate the solar.
> Sweden is just about the worst case, there's very few countries/people that far north.
Sweden is worse but it's still a significant issue in e.g. New York or Paris or Auckland.
> There's genius invention called "wires". HVDC has transmission losses on the order of 3.5% per 1,000km. You don't have to colocate the solar.
It's more than 1000km from the places that get cold to a part of the world where it isn't winter.
Suppose we ignore that it's winter in the US Northeast and Southeast at the same time and run HVDC 2000+ km to Florida because it gets an extra hour of sunlight. Long distance transmission can't be used to counter seasonal output and regional weather at the same time because one requires the generation to be spread everywhere and the other requires it to be concentrated closer to the equator. If we concentrate the solar in Florida to mitigate winter in New England then we're screwed when Florida is overcast.
> it's still a significant issue in e.g. New York or Paris or Auckland.
No it isn't.
Wires still might be worth it, but these are all close enough to the equator that you can just over provision locally without issue if you prefer.
> It's more than 1000km from the places that get cold
Solar panels work better in the cold. The issue is with how far from the equator Sweden is, not how cold it is.
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Wires and HVDC transmissions are nice, but they have a fairly large downside. They are major infrastructure projects that cost a lot of money and they don't produce any energy. Adding that cost to the solar panels makes them significantly more expensive, and solar/wind farms owners are not exactly willing to bear that cost.
You don't need to colocate the solar, but you need to make sure you can get that power when you actually need it.
During crisis nations are going to restrict exporting electricity and prioritizing their own residents. Electricity that is generated in Germany is not going to warm up Nordic countries if Germany doesn't let it.
Wires are also susceptible to sabotage, especially undersea ones (which are the current major connection points to Europe).
The issue is more the other way at the moment. Norwegian prices can get high as they are exposed to German demand over the interconnector.
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